1. Field of the Invention
This invention relates to an abrasive cleaning apparatus having a plurality of arms rotatably pivoted together to permit movement of an abrasive nozzle relative to a work surface.
2. Description of the Prior Art
Sand blasting of surfaces prior to painting or simply cleaning, as in the case of stone or brick walls, is a common practice. Generally, sand blasting is accomplished by an operator positioned on a scaffold or other suitable support manually manipulating a single discharge nozzle. Obviously, the presence of the operator in the work zone makes sand blasting an extremely dirty and hazardous occupation. Moreover, the limited volume of the sand blasted against the work surface by a single nozzle is inefficient for many tasks.
As a result, the abrasive blast apparati used for large surface areas may employ multiple rather than a single blast nozzle. Multiple nozzles substantially increase the area of the blast pattern. Due to the increased weight and speed of the cleaning operation, the multiple nozzles and the operator are often mounted on a moveable carriage or platform which is movable laterally and vertically along the work surface.
Unfortunately a number of difficulties have been experienced which hinder general acceptance and wide use of the multi-nozzle sand blasting apparatus. For example, multi-nozzle heads are of a type in which the sand and air are delivered and mixed in a common reservoir. The sand and the air are propelled simultaneously from the nozzles with all nozzles communicating directly with the common reservoir. In another configuration, each of the plural nozzles is provided with a separate supply line. In either of these arrangements, individual control of the angle of the nozzles is lacking in the prior art multiple nozzle apparati. Such manipulations of the blast angle of the nozzles is desirable in situations involving areas which present difficult cleaning problems. The blast from one nozzle must work on the difficult cleaning area for a prolonged period, during which time the other blast nozzles will blast at the surrounding areas.
Another difficulty with prior art multi-blast carriage arrangements is that the units are very cumbersome and complex so as to be suitable only for special cleaning operations. In addition, many prior art multiple nozzle machines lack adequate flexibility of movement and are not easily adaptable to various sand blasting tasks.
In my first patent, U.S. Pat. No. 4,027,433, I disclosed a novel arrangement for plural sand blasting nozzles. In this arrangement, the nozzles were disposed substantially parallel to one another and adapted for angular adjustment relative to the work surface. This patent overcame many disadvantages found in the prior art multiple nozzle devices.
In my second patent, U.S. Pat. No. 4,126,970, I disclosed a novel arrangement for utilizing the reaction force of a nozzle disposed in an angular adjustment relationship as in my first patent, U.S. Pat. No. 4,027,433. This invention was particularly suitable for cleaning the top or underside of a substantially horizontal surface.
In my third patent, U.S. Pat. No. 4,139,970, I disclosed another multiple nozzle apparatus utilizing the plural nozzle arrangement set forth in my first patent, U.S. Pat. No. 4,027,433. This invention is very desirable for cleaning a vertical surface since the operator is positioned on the apparatus with the plurality of nozzles mounted upon three perpendicular axes to obtain the proper blast angle relative to the work surface. The apparatus was adapted for elevation on a mobile lift platform making the apparatus suitable for blasting large vertical surface areas such as ships' hulls, oil tanks and other massive structures.
Finally, in my fourth invention, Ser. No. 963,689, filed Nov. 27, 1978, I disclosed an improvement over my second patent, U.S. Pat. No. 4,126,970, by providing an apparatus which requires minimal physical manipulation by an operator. An actuator rotates the abrasive cleaning nozzle about a second axis to control the reaction force nozzle enabling automatic alternate sweeping across the work surface about a first axis.
The above-mentioned patents have been proven to be most helpful in sand blasting massive structures. Experience has shown, however, that there exists great difficulty in cleaning structures having irregular shapes. Specifically, such irregular shapes may comprise doors, eaves, and other protuberances. To clean such irregular shapes, the prior art sand blasting devices teach the use of a single hand held nozzle which must be manually manipulated by the operator to direct the flow of the abrasive material about the surface of the irregular-shaped structure. As noted earlier, the presence of the operator in the work zone makes sandblasting an extremely dirty and hazardous occupation. Moreover, the limited volume of the sand blasted against the work surface by a single nozzle is time consuming and therefore economically inefficient for many tasks.
It is a primary objective of the present invention to provide a universal apparatus for cleaning a work surface with an abrasive under fluid pressure in a manner similar to those disclosed in my prior patents and further to clean irregular-shaped structures.
Another object of this invention is to provide an apparatus for cleaning a work surface with an abrasive under fluid pressure comprising a plurality of arms which are rotatably connected in series with one another and a plurality of nozzles disposed at the distal end of the arms to be positioned relative to the work surface by manipulation of the arms.
Another object of this invention is to provide an apparatus for cleaning a work surface with an abrasive under fluid pressure wherein the conduits connecting the nozzles to the source of abrasive and fluid are disposed within the interior of the arms thereby protecting the conduits from damage.
Another object of this invention is to provide an apparatus for cleaning a work surface with an abrasive under fluid pressure including actuator means for rotating each of the arms with respect to one another to direct the stream of the abrasive and fluid emitted from the nozzles at the work surface.
Another object of this invention is to provide an apparatus for cleaning a work surface with an abrasive under fluid pressure including means for physically controlling the actuator means thereby enabling the operator to selectively direct the stream of abrasive and fluid emitted from the nozzles at selected positions of the work surface.
Another object of this invention is to provide an apparatus for cleaning a work surface with an abrasive under fluid pressure including means for automatically controlling the actuation means to direct the stream of abrasive and fluid pressure emitted from the nozzle to sweep the work surface in a pre-programmable pattern.
Another object of this invention is to provide an apparatus for cleaning a work surface with an abrasive under fluid pressure wherein the proximal end of the series of arms is connected to a rotatable drum for rotation of the series of arms about the rotational axis of the drum.
Another object of this invention is to provide an apparatus for cleaning a work surface with an abrasive under fluid pressure including a brake means for braking the drum.
The foregoing has outlined some of the more pertinent objects of the invention. These objects should be construed as merely illustrative of some of the more prominent features and applications of the intended invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the summary of the invention and the detailed description describing the preferred embodiment, in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.